The VCRC Clinical Outcomes Program leverages the network of VCRC sites with expertise in the clinical care of patients with vasculitis to conduct high-quality clinical outcomes research in rare diseases. Patients with different forms of vasculitis are comprehensively phenotyped at multiple time points in the disease course in both observational and clinical trial settings. The long-term goal of the VCRC Clinical Data Outcomes Program is to improve clinical outcomes of patients with all types of vasculitis through improved understanding of the natural history, epidemiology, and efficacy of therapeutic interventions. The objective of the program is to study clinical outcomes in parallel across seven primary types of vasculitis. The rationale to the approach is that multi-center research in rare diseases using standardized data collection practices is an efficient and effective method to conduct high-quality clinical outcomes research in rare diseases. The specific aims of this project are: 1. Maintain the infrastructure that supplies, stores and utilizes all clinical data collected in the VCRC Longitudinal Studies and clinical trials within the VCRC Clinical Data Repository for clinical outcomes research in vasculitis; 2. Conduct meaningful clinical outcomes research in vasculitis using prospectively-collected data in the following areas: natural history studies, clinical outcome studies, and outcome measure assessments. 3. Facilitate interaction among VCRC members focused on the use of clinical data that promotes the training of young investigators and the development of novel analytic approaches to rare disease research. By leveraging existing infrastructure within the VCRC, including the VCRC Longitudinal Studies, VCRC-led clinical trials, the VCRC Clinical Data Repository, and the expertise of the VCRC Steering Committee, the VCRC Clinical Data Outcomes Program overcomes challenges common to rare disease research. The collaborative effort required of the VCRC centers to complete initiatives within the VCRC Clinical Outcomes Program serves as a template for conducting research in rare diseases.